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Implemented binary insertion sort algorithm

This commit is contained in:
Gregory Eremin 2015-10-12 00:27:04 +03:00
parent dee0e10404
commit 4b090b48ea
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GPG Key ID: 5EFA427EEC26E86C
4 changed files with 81 additions and 30 deletions

28
binary_insertion_sort.go Normal file
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@ -0,0 +1,28 @@
package algorithms
// BinaryInsertionSort is an implementation of binary insertion sort algorithm.
// Wikipedia: https://en.wikipedia.org/wiki/Insertion_sort#Variants
func BinaryInsertionSort(a []int) []int {
for i := 1; i < len(a); i++ {
v := a[i]
low := 0
high := i
for low < high {
mid := low + (high-low)/2
if v < a[mid] {
high = mid
} else {
low = mid + 1
}
}
for j := i; j > low; j-- {
a[j] = a[j-1]
}
a[low] = v
}
return a
}

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@ -0,0 +1,18 @@
package algorithms
import (
"testing"
)
func TestBinaryInsertionSort(t *testing.T) {
testSort(t, BinaryInsertionSort,
[]int{5, 3, 1, 4, 2},
[]int{1, 2, 3, 4, 5},
)
}
func BenchmarkBinaryInsertionSort(b *testing.B) {
for i := 0; i < b.N; i++ {
BinaryInsertionSort(unsortedArray())
}
}

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@ -5,21 +5,21 @@ import (
) )
func TestInsertionSort(t *testing.T) { func TestInsertionSort(t *testing.T) {
testInsertionSort(t, InsertionSort, testSort(t, InsertionSort,
[]int{5, 3, 1, 4, 2}, []int{5, 3, 1, 4, 2},
[]int{1, 2, 3, 4, 5}, []int{1, 2, 3, 4, 5},
) )
} }
func TestInsertionSortOptimized(t *testing.T) { func TestInsertionSortOptimized(t *testing.T) {
testInsertionSort(t, InsertionSortOptimized, testSort(t, InsertionSortOptimized,
[]int{5, 3, 1, 4, 2}, []int{5, 3, 1, 4, 2},
[]int{1, 2, 3, 4, 5}, []int{1, 2, 3, 4, 5},
) )
} }
func TestInsertionSortOptimizedTwoItems(t *testing.T) { func TestInsertionSortOptimizedTwoItems(t *testing.T) {
testInsertionSort(t, InsertionSortOptimized, testSort(t, InsertionSortOptimized,
[]int{2, 1}, []int{2, 1},
[]int{1, 2}, []int{1, 2},
) )
@ -36,30 +36,3 @@ func BenchmarkInsertionSortOptimized(b *testing.B) {
InsertionSortOptimized(unsortedArray()) InsertionSortOptimized(unsortedArray())
} }
} }
func testInsertionSort(t *testing.T, sortFun func([]int) []int, a, exp []int) {
s := sortFun(a)
if len(s) != len(exp) {
t.Fatal("Array sizes don't match")
}
for i := 0; i < len(exp); i++ {
if s[i] != exp[i] {
t.Fatalf("Expected sorted array to equal %v, got %v", exp, s)
}
}
}
func unsortedArray() []int {
return []int{
57, 64, 83, 25, 26, 10, 55, 22, 76, 61,
28, 77, 56, 32, 63, 17, 91, 20, 58, 16,
1, 51, 88, 82, 24, 70, 81, 35, 49, 39,
89, 30, 46, 6, 41, 19, 43, 67, 53, 97,
65, 37, 13, 23, 29, 69, 0, 73, 9, 59,
96, 34, 66, 79, 27, 14, 40, 80, 98, 2,
5, 45, 50, 4, 85, 18, 86, 7, 87, 31,
95, 47, 68, 36, 15, 48, 8, 92, 11, 74,
78, 52, 44, 42, 54, 84, 12, 21, 38, 99,
72, 33, 71, 93, 60, 62, 90, 94, 3, 75,
}
}

32
sort_test.go Normal file
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@ -0,0 +1,32 @@
package algorithms
import (
"testing"
)
func testSort(t *testing.T, sortFun func([]int) []int, a, exp []int) {
s := sortFun(a)
if len(s) != len(exp) {
t.Fatal("Array sizes don't match")
}
for i := 0; i < len(exp); i++ {
if s[i] != exp[i] {
t.Fatalf("Expected sorted array to equal %v, got %v", exp, s)
}
}
}
func unsortedArray() []int {
return []int{
57, 64, 83, 25, 26, 10, 55, 22, 76, 61,
28, 77, 56, 32, 63, 17, 91, 20, 58, 16,
1, 51, 88, 82, 24, 70, 81, 35, 49, 39,
89, 30, 46, 6, 41, 19, 43, 67, 53, 97,
65, 37, 13, 23, 29, 69, 0, 73, 9, 59,
96, 34, 66, 79, 27, 14, 40, 80, 98, 2,
5, 45, 50, 4, 85, 18, 86, 7, 87, 31,
95, 47, 68, 36, 15, 48, 8, 92, 11, 74,
78, 52, 44, 42, 54, 84, 12, 21, 38, 99,
72, 33, 71, 93, 60, 62, 90, 94, 3, 75,
}
}